The present invention relates, in general, to a tester for electronic fuel injectors, and, more particularly, to an electronic fuel injector testing probe that produces a visual and audible signal each time the pintle within the fuel injector being tested opens.
Testers to determine whether fuel injectors are operating properly are readily available. For example, U.S. Pat. No. 4,523,458 (Daniel) discloses a fuel injector tester which utilizes a piezoelectric crystal that converts mechanical impulses caused by the actuation of the pintle within the fuel injector into electrical signals. In this case, the piezoelectric crystal is comprised of two piezoelectric substrates with a metal layer interposed therebetween. The piezoelectric crystal is interposed between permanent magnets, one permanent magnet allowing the tester to be magnetically attached to the fuel injector being tested. The permanent magnets are provided with end plates which retain the piezoelectric crystal permitting the mechanical vibrations of the end plates, caused by the opening of the pintle within the fuel injector tester, to be transmitted to the piezoelectric crystal wherein the vibrations are converted into voltage signals. The resulting structure of the tester disclosed in this reference is rather complex since it includes two piezoelectric substrates with a metal layer interposed therebetween and also includes permanent magnets and end plates to retain the piezoelectric crystal and to transmit mechanical vibrations from the fuel injector to the piezoelectric crystal.
The Pool, et. al. reference (U.S. Pat. No. 6,260,412) discloses a device for testing the output control voltage of an electronic fuel injection system. The invention disclosed in this reference is directed to a device that can be used to test a fuel injection control system to determine if it is producing the necessary electrical signals required to actuate the fuel injectors. As such, the device disclosed in this reference cannot be used to test the operation of the fuel injectors individually.
The VanTassel, et. al. reference (U.S. Pat. No. 4,141,243) discloses apparatus for measuring the volumetric output of fuel injector system components, such as a fuel injector and/or a fuel pump. As such, by measuring the volumetric output of a fuel injector, a determination can be made as to whether the fuel injector is operating properly. In this case, the volumetric output of the fuel injector must be measured in order to evaluate the operability of the injector, and thus, a direct determination cannot be made as to whether the fuel injector is operating properly.
The present invention solves the problems associated with the prior art fuel injector testers, and other problems, by providing an electronic fuel injector testing probe which permits individual fuel injectors to be tested when the car is at idle. The fuel injector testing probe of the present invention detects the impact or vibration which occurs when the pintle within a fuel injector opens by using a piezoelectric transducer which is provided in the pistol-type handle of the probe. A light emitting diode is provided in the pistol-type handle and flashes each time the pintle within the fuel injector opens. In addition, the testing probe emits an audible sound each time the pintle within the fuel injector opens.
The electronic fuel injector testing probe of the present invention remains in the xe2x80x9csleepxe2x80x9d mode when not in use. The testing probe is activated by tapping the probe on a hard surface. Once the testing probe is xe2x80x9cawakenedxe2x80x9d, the light emitting diode flashes and the probe emits an audible sound. The tip of the testing probe can then be placed against the body of the fuel injector being tested to determine whether the fuel injector is operating properly. Opening of the pintle within the fuel injector causes both the light emitting diode within the pistol-type handle of the testing probe to flash and the probe to emit an audible sound. When testing has been completed, the fuel injector testing probe emits an audible sound, flashes and then goes back into the xe2x80x9csleepxe2x80x9d mode.